The strike, on Tuesday in Tabqah, Syria, was the third time in a month that American-led airstrikes may have killed civilians or allies, and it comes even as the Pentagon is investigating two previous airstrikes that killed or wounded scores of civilians in a mosque complex in Syria and in a building in the west of Mosul, Iraq.

In the above sentences, does "that American-led airstrikes may have killed civilians or allies" modify "a month"?